Method of treating metals



Patented June 10, 1924.

UNITED STATES PATENT OFFICE.

METHOD OF 'IfRJilA'J.ING METALS.

No Drawing.

To all whom it may comer n. Be it known that I, GUSTAV F. GERo'rs,citizen of the Republic of Germany, residing at Bremen, Germany, haveinvented new and useful Improvements in Methods of Treating Metals, ofwhich the following is a specification.

My invention relates to .a method of producing metal castings subject tovarying strains, use being made of a low grade basic has shown, themetal in most cases is sooverheated that a large part of the mostvaluable constituents burn out and the casting 'is then not capable ofwithstanding the load put thereon in actual use. Even in ouring themetal out of crucibles it is di cult to avoid burning as a result ofoverheating, because the temperature for pouring must be higher than thefusing temperature in order to secure complete castings, but so far as Iam aware there are no simple suitable means in existence for preciselydetermining this temperature.

According to the present invention however, only low grade basic metalis used and this low grade metal-is made adaptable for producingbearings capable of sustaining substantial loads by adding to a definitequantity, by weight, of the fused basic metal an addition body whichcontains the reuired constituents for producing the de-' sired greaterhomogeneity or other property of the metal. To these addition bodiesother substances may be added which without having the property ofmodifying the casting may so increase the fusing or meltlng point of theindividual addition bodles that the fusion thereof at the same timegives an indication of the time for pouring whereby overheating of themolten metal issafely avoided.

Application filed January 18, 1928. Serial No. 812,517.

For example, according to my invention, for the purpose of producing orcasting bearings subject to greatly varying loads it is necessary tohave in stock only hard lead alloy which suflices for bearings subjectto very low load and is made ada table for higher load bearings by theadditlon thereto of the correspondin addition bodies. The additionbodies are esignated to correspond with the fusion metal or basic metalin connection with which they are adapted to be used to give the correctconstitution or the correct temperature for pouring, while for the useof the basic metal alone only addition bodies are employed which do notaffeet the molten metal but simply, by their fusion, indicate thecorrect pouring temperature and are so designated.

I am, of course, aware that it is very common .in foundry practice tochange the character of a metal or of an alloy by adding another metalthereto. But I believe I am the first to make it possible for anordinary unskilled workman to ada t low grade or basicmetal for anydesire purpose and to determine the precise temperature at which themolten metal is to be poured. It is not always possible for a skilledfoundryman to predete'rmrne the proper pouring temperature of the moltenmetal, and the usually adopted expedient of immersing a bar of wood inthe metal is unreliable because of the varying degrees of moisture ofthe wood.

By means of the present invention any workman, without previous trainingin foundry practice or metallurgy, is enabled to adapt a low grade metalor alloy for any desired urpose and by the use of the addition bodieswhich form the required alloy the precise prescribed pouring temperatureis indicated.

The following example will serve to demonstrate the application of theinvention in ractice.

ssuming that in a shop or factory four different kinds of bearing are inuse as follows 1.. Ordinary bearings for 1i ht loads.

2. Bearings for medium loa s 3. Bearings for heavy loads (bearings forpropeller shafts) 4...,Bearings for railway carriages, etc. and forthese bearings the following four alloys, with the indicated ballpressure hardness and melting points, are. used Alloy. 11

Metl. No. g ggf pgglt,

Pb Sb Sn ness.

number 1 to serve as a basic metal, because by adding thereto the properaddition body, alloys numbers 2, 3 and 4: are automatically roduced. Foralloy number 1 an addition body would be used which does not modify themetal and merely indicates, when it.

melts, the proper ouring temperature of the molten metal. T e followingtable shows the composition, the melting point and the approximate sizeof the addition bodies.

N Ailey. M5212 Size, mm. 23 0. high.

Pb Sb Sn If there be added to the basic metal, per k' an addition bodyas above the desired afioy will be obtained. For example, b adding toone kg. of the basic metal an a dition body 3 the resulting alloy willcorrespond exactly to the alloy 3 in the first table, and at the sametime the melting of the addition body indicates precisely the properpouring temperature which, in this case, is 360 1., i. e. 85 higher thanthe melting temperature of alloy number 3. Thus unintentional oraccidental overheatin is guarded against.

%he addition body 1 indicates only pouring temperature, about 80 higherthan the melting temperature of alloy number 1, while the meltingtemperature of the addition body number 3 is about 90 higher than themelting temperature of the alloy number 3 and thus serves, per se, as anindex to the pouring temperature. The melting point of addition bodynumber 2 is 400 C. and, in order that this temperature may be only about80 higher than the melting temperature of alloy 2, the addition body 2has added thereto a small quantity of a metal (such as bismuth) whichlowers the melting temperature to about 360 C. but

but which, by reason of the small quantity used, does not affect theproperties of the basic metal. In the foregoing table the additionbodies are indicated by numbers 1 to 4, but even without thesenumbers'the bodies could be distinguished from each other because oftheir diiference in size, the increasing in size from number 1 to number.4 being uniform.

The procedure according to my invention is very simple and requires nospecial attention on the part of the operator. As soon as the basicmetal has been melted, the slag layer is removed from the middle of thecrucible of fusion chamber and the addition body is laid on the fiuidmetal bath, such addition body corresponding to the'load which thecasting is to withstand. As soon as the addition body has melted theentire mass is stirred and then immediately poured, because when theaddition body melts the correct temperature for pouring is reached.

To prevent oxidation of the surface of the metal bath, the additionbodies may be combined with a de-oxidizing mass, such as alkalicarbonate, borax, etc., which immediately upon contacting with the hotsurface of the metal melts and covers the latter. This protective massmay be enclosed by the addition body like a capsule or may partly orentirely enclose'it, in order to protect the addition body againstoxidation.

Claims:

1. The herein described method of adapting low grade metal to desireduses. which ing low grade metal to desired uses, which consists inadding to the molten metal for each given unit of weight thereof a metaladdition body which imparts improved qualities to the molten metal andwhich addition body, when it melts, indicates the correct pouringtemperature of the molten metal.

3. An addition body for low grade metals, comprising a metal alloyhaving a melting temperature indicative of the proper pouringtemperature of the molten metal to which the addition body is added.

4. An addition body as claimed in claim 3 combined with a de-oxidizingprotective mass.

In testimony whereof I have aflixed my signature.

GUSTAV F. GERDTS. WVitnesses FRANCIS J DUGAN, AUGUST (30101:.

